Generally, almost 65% of the total calorie intake should be acquired from carbohydrates according to the standard nutritional guidelines. Proteins represent a very small portion in the ideal balanced diet while fat represents almost one-third of the total caloric content. MORE Â».
The trench is then backfilled, and additional material added to the top. Both of the Baltimore tunnels (the Harbor Tunnel and Fort McHenry Tunnel) used this method in their construction. The Harbor Tunnel, built in the mid-1950s, was considered an engineering marvel.
Light at end of tunnel after 17 years' work. The rough design for a rail tunnel under the Gotthard Pass was first sketched by Swiss engineer Carl Eduard Gruner in 1947. But bureaucratic delays, concerns over the cost and other hurdles pushed back the start of construction until 1999.